Add ansible-lint and fix all warnings and errors

This repository had an old version of the linting CI, so this was updated. However, the only warning left seems to be ignoring its ignore-tag... The line in defaults/main.yml has a # noqa line-length, but yaml still complains about it. I have no idea how to fix this.

EDIT: fixed it - it has to be # noqa yaml[line-length] instead.